40 EA

COTTAGE | Water Heater

1600 – 4000 W
5,400 – 13,600 BTU

Wallas 40 EA water heater

Water Heater That is Both Functional and Beautiful

Wallas 40 EA is a water heating system for off-grid cottages that can be used solely as a hot water heater for domestic water or it can also power up underfloor heating and radiators. Underfloor water heating system is an excellent alternative to air heating as it disperses dry heat evenly in the space and provides an added luxury of having comfortably warm floors to walk on. When water is run underneath the flooring, there is no air blowing in the space, which can also be a relief to some, if allergies are a concern. 

Energy-efficient diesel heater requires only about 0,2-04 amps, which is why a small solar panel is sufficient to recharge the battery. The fuel consumption is also so low, that a 33 liter (6 gal.) fuel tank will keep the heater running for almost six days. Wallas particularly recommends the Neste MY Renewable Diesel™, which is high-performing low carbon biofuel.  

The modern design of Wallas 40 EA is both functional and beautiful, and comes in two color options: graphite gray and winter white, which match any decor. The unit and fuel tank can also be installed in a utility room away from the eyes. 40 EA cottage heater is widely used in the Nordic Countries and it has been found to be an excellent heating option for cool summer evenings as well as freezing cold winter nights. You can easily transform your cottage into a perfect resting spot, where you can relax with family and friends year-round. 


Advanced Control Panel

If 40 EA is used solely as a domestic water tank heater, all you need to do is turn it ON or OFF

If a second water pump is installed for floor heating, the control panel allows you to set a target temperature and the thermostat maintains a smooth ambient temperature in the space

The simple display shows all the information you need 

Wallas Remote App for Remote Access

Turn your heater on remotely with the Wallas Remote App and enjoy warm water and a warm cottage upon arrival

Monitor indoor temperature and battery voltage remotely from home to be better prepared for the day

Adjust temperature locally with your phone without having to reach to the control panel

Keep your heater always updated with the latest features



Cleaner Burning

Updated software optimizes fuel consumption

Calibrated to burn renewable fossil free diesel (e.g. HVO)

Larger burner burns fuel slower resulting in ultra low NOX emissions

Extensively tested with Neste

Improved burner efficiency for more power

The Greenboost burner burns renewable fossil-free diesel cleanly and energy-efficiently

Combustion air is pulled in from the outside ensuring fresh airflow indoors

Exhaust gas is safely expelled outside keeping the indoor air clean and odourless 

Fully enclosed laminar burning process ensures a quiet sound level and dries the indoor air

Unit can be used to power up a water boiler, underfloor heating, or radiators

Brushless blower motor has a longer life-cycle and requires less frequent servicing 

Durable Finnish design and manufacturing keep your heater intact for years

Low temperature on unit and exhaust pipe for everyone’ safety

12 V battery is easy to recharge with a small solar panel

Alternatively, the unit can be used in 110V/230V network with a 12 V converter

Advanced Control Panel enables intelligent temperature control

Wallas app heater control works locally at the cottage with no Wifi by using short-distance wireless connection

Heater can be accessed from any location through a WiFi modem with the Wallas App

Remote accessibility enables system updates and diagnostics


Wallas 40 EA power


Wallas 40 EA fuel



Fuel: Diesel, HVO renewable diesel
Power: 1600-4000 W (5,400-13,600 BTU)
Operating Voltage: 12 V 
Fuel Consumption: 0,16-0,40 l/h (5.4-13.5 oz/h)
Electricity Consumption: 0,2-0,4A
Energy efficiency index: A+
Length: 478 mm (18 13/16″)
Width: 305 mm (12 1/64″)
Height: 740 mm (29 9/64″)
Weight: 25 kg (55 lbs.)
Colors: Graphite gray, winter white

Choose from two beautiful colors: graphite gray or winter white


Area: 60-90 m² (645-970 ft²)

Floating houses, tiny houses, container houses, cottages, houseboats


Heater without the front panel (to be chosen separately)
Advanced Control Panel, wire 5 m (16 ft)
Power cable with connector and integrated fuse 4 m (13 ft)
Fuel line 4 m (13 ft)
Separate tank feed
Accessory bag including essential clamps and screws


Stainless Steel, High-Grade Aluminum, Other Corrosion-Resistant Materials

Technical values are measured in a reference measurement wall, which is constructed to respond to a typical cottage installation. Values have been measured with maximum length of ducting, exhaust pipe, fuel line, and power cord. The figures allow for 10 % reserve – yours may vary.

Wallas heaters and stoves are designed to run with standard road and boat diesel, as well as renewable fossil free diesel. Check with your distributor for further details on best options for your needs.

Wallas 40 EA dimensions

Accessories in black are included in the standard package. Accessories in blue are additional. 

Wallas 40 EA dimensions
Wallas 40 EA water heater

Browse product manuals, spec sheets and more in the Documents Center

Is an Air Heater More What You Are Looking for?

If a water heating system is not exactly what you are looking for, take a look at Wallas air heaters for cottages:

Reach out to your dealer to discuss different installation options and ensure you get what you need.